Blood purification systems, which are used for conducting hemodialysis, hemodiafiltration or hemofiltration, involve the extracorporeal circulation of blood through an exchanger having a semi-permeable membrane. Such systems further include a hydraulic system for circulating blood and a hydraulic system for circulating replacement fluid or dialysate comprising the certain blood electrolytes in concentrations close to those of the blood of a healthy subject. Most of the conventionally available blood purification systems are, however, quite bulky in size and difficult to operate. Further, the design of these systems makes them unwieldy and not conducive to the use and installation of disposable components.
Standard dialysis treatment, using an installed apparatus in hospitals, comprises two phases, namely, (a) dialysis, in which toxic substances and scoriae (normally small molecules) pass through the semi-permeable membrane from the blood to the dialysis liquid, and (b) ultrafiltration, in which a pressure difference between the blood circuit and the dialysate circuit, more precisely a reduced pressure in the latter circuit, causes the blood content of water to be reduced by a predetermined amount.
Dialysis procedures using standard equipment tend to be cumbersome as well as costly, and generally require the patient to be bound to a dialysis center for long durations. While portable dialysis systems have been developed, conventional portable dialysis systems suffer from certain disadvantages. First, they are not sufficiently modular, thereby preventing the easy setup, movement, shipping, and maintenance of the systems. Second, the systems are not simplified enough for reliable, accurate use by a patient. The systems' interfaces and methods of using disposable components are subject to misuse and/or errors in usage by patients. For a portable dialysis system to be truly effective, it should be easily and readily used by individuals who are not health-care professionals, with the design of disposables and data input sufficiently constrained to prevent inaccurate use.
For example, one common problem encountered during a hemodialysis treatment is the appearance of an air bubble in the venous bloodline tubing going to the patient. An air bubble is detected typically by an occlusion detector in the system. Subsequently, the user (such as a technician/clinician or nurse) is required to move the air bubble to a different part of the tubing, where it can safely be removed. Typically, the bubble is positioned under a needleless port inline on the tubing for removal. Correct positioning of the air bubble is conventionally achieved with a push-hold-release mechanism, wherein the user presses, holds or releases a button repeatedly to move the bubble forward or backward until it reaches the desired position. Working with this kind of mechanism may prove complicated since the user may not have the dexterity or the reaction times necessary to move the air bubble quickly and accurately. This may result in a frustrating experience for the patient, besides being a potentially dangerous situation if the air bubble is not correctly removed.
Consequently, there is need for an improved apparatus and method for detecting and removing air bubbles in a venous line. Such a system should provide assistance to the user to accurately position the air bubble and simplify the process of air bubble removal.